Pipe coupling



June 15, 1948. c, H0555 2,443,187

PIPE COUPLING Filed Aug. 15, 1944 2 Sheets-Sheet 1 39 INVENTOR. 30 3 83/ IA M55 6. #0235 A TTOIP/VEYS June 15, 1948. c, HOBBS 2,443,187

PIPE COUPLING 2 Sheets-Sheet 2 \I y I v o Filed Aug. 15, 1944 Fig-7 as J\ INVENTOR.

JAMES C. #0555 JUL 26 I949 Patented June 15, 1948 UNITED STATES PIPECOUPLING James 0. Hobbs, Peimsviue, Ohio 6 Application August 15, 1944,Serial No. 549,533

.5 JUL 26 I949 Claims. \01. 285-:86)

This invention relates generally to fluid seals and more particularly tonew seals for the ends of pipes carrying fluids under high pressure.

A great many efforts have been made heretofore to prevent the escape offluids at the ends of pipes, as in pipe couplings, joints and the like.Some of the seals proposed were fairly satisfactory in sealing againstescape of low pressure fluids while other seals werefairly satisfactoryin sealing thick walled pipes against escape of fluid under fairly highpressure. Most of the prior high pressure seals were heavy, cumbersomeand expensive, and few, if any, of them were capable of sealing fluidpressures on the order of 1500 pounds per square inch or more whensubject to rapid temperature changes.

The present invention provides a simple, light, inexpensive seal whichis capable of sealing against escape of fluids whose pressures range allthe way up to 10,000 pounds per square inch or more. Suchseals may beused with pipes whose thicknesses range from a very thin wall such, forexample, as 0.02 inch up to heavy walls such, for example, as severalinches. Furthermore, the sealing effect of seals embodying the presentinvention increases with increases in forces tending to separate thepipe axially from its associated member and also increases withincreases in the sealing force applied to the seal. From what has justbeen stated it will be apparent that the present invention provides anew seal which is capable of many different applications and which isnot only better in many respects than prior seals but is much moreeffective in operation. Furthermore, as will be pointed out more indetail hereinafter, the mode of operation of seals embodying the presentinvention is new and different from the modes of operation of all otherprior seals with which I am familiar.

In the drawings accompanying and forming a part of this specificationand showing various forms of apparatus embodying this invention,

Figure 1 is a fragmentary, sectional view showing a seal at the junctionof a pipe end and a hollow member extending transversely to thelongitudinal axis of the pipe;

Figure 2 is an enlarged view of parts of Fig. 1;

Figure 3 is a fragmentary, sectional view similar to Fig. 1, but showinga modified form of seal;

Figure 4 is a fragmentary, cross-sectional view of a seal between a pipeend and an aligned coupling;

Figure 5 is a view similar to Fig. 4 but showing a modified form of pipeend and sealing ring;

Figure 6 is a fragmentary, cross-sectional view of a seal at thetelescoped ends of'two pipes, one of which is flanged;

Figure 7 is a fragmentary, cross-sectional view of a seal at theJunction of a flanged coupling and a pipe end and illustrating theapplication of forces to the seal and the effect of those forces on thesealing action of the device;

Figure 8 is a fragmentary, cross-sectional view resembling Fig. 7 incertain respects but illustrating the resolution of sealing forces bythe threads on the flanged coupling;

Figure 9 is a view similar to Fig. '7 but showing deformable packing inconjunction with the sealing ring;

Figure 10 is a view similar to Fig. 9 but showing a modified pipe endand sealing ring with deformable packing.

In Figs. 1 and 2 the pipe I has an outwardly flared portion 2 near oneend and a concentric lip 3. The outer surface 4 of portion 2 is conicalwith the base of the cone being nearer the end of the pipe. The conicalsurface 4 is inclined at an angle of approximately 45 degrees to thelongitudinal center line of the pipe.

The member 5 extends transversely to pipe I and has a longitudinalpassage 6 and a side passage 1. The face of member 5 opposed to pipe Iis provided with an annular groove 8 around passage I and defined inpart by radially spaced inner and outer surfaces 9 and I0. The lip 3 ofpipe I extends into this groove 8 and may be supported on the innersurface 9 against forces applied to the exterior of pipe I by thesealing ring. Surface III is extended outwardly to surround the conicalsurface 4 on pipe I and to define therewith an annular space II which istriangular in cross-section.

The annular pad I2. constituting part of member 5, is provided with aplurality of threaded openings to receive studs I3. Retaining andsealing ring I4 is provided with a corresponding number of openings toreceive studs I3 and may be urged toward member 5 by nuts I5 on thestuds.

Ring I4 is provided with an annular flange I6 which has a substantiallycylindrical outersurface and an annular depression I'I near its .freeend. A sealing ring I8, which may be composed of softer metal than thatof the pipe I or member 50 5, is disposed in depression I! and securedto flange I6. The end surfaces of ring I8 and flange I6 form a conicalsurface I9 which is inclined at an angle of approximately 44 degrees tothe longitudinal center line of pipe I. The base of 55 the conicalsurface I9 is at or near the thin edge suriace 4 near its base.

I substantially like that 3 thin end of the ring and whose proximatelyline of pipe 30. At its thick end ring 31 has a substantiallycylindrical surface '48 whose diamof flange I6 and is engageable withthe conical When the pipe I, member 5 and ring I8 are assembledsubstantially as shown in Figs. 1 and 2, and the, nuts I5 are turned onstuds I3 so as to force flange I6 into the annular space between 01 pipeI, the flange I6 will be deflected outwardly so that, the outer surfaceof .the ring I8 will make substantially a line contact with surface Iand the conical surface I9. It will also make substantially a linecontact with conical surface 4. These two lines will lie insubstantially the same plane transverse to the pipe I. Theselinecontacts constitute eflectiveseals against escape of fluid underpressure between those surfaces. The angularity of annular space I!which is defined by surfaces 4 and I9 is the difference between the 45degrees of surfat-e 4 and the 44 degrees of surface I9, or approximatelyone degree. Oneimportant advantage of a small space of approximately onedegree is that the sealing contacts may be narrow and, therefore,fluidtight and that they may increase in width under increasingpressure, but as the pressure increases the'Ldeflection of the sealingmember is resisted more and more strongly and over wider and wider areasuntil the conical surface of that member 7 may make contact forsubstantially its full axial .length with the opposed conical surface.However, this is an extreme and tion.

While pipe I is shown as having a wall of substantial thickness, itwillbe understood that the pipe wall may be much thinner than thatillustrated, for the support afforded by surface 9 of exceptionalcondisurface II) of member and conical surface 4 eter is only slightlygreater than the outside diameter of pipe 38. I

When the parts are assembled as shown in Fig. 4 and ring 38 is rotatedto urge seal ring 31 toward the right, the inner surface 39 of ring 31makes substantially a. line contact with the opposed conical surface 39of pipe and the ring is deflected into substantially a line contact ofits outer surface 38 with the opposed surface of the coupling. These twosubstantially line contacts are approximately in a plane at rightanglesto the longitudinal center line of pipe 36 and afford good seals toprevent escape of fluid under pressure from the interior of pipe 38 andpast ring 31. The surface 33 of coupling 34 affords internal supportadequate to prevent the crushing or distortion of the pipe end even whenthe pipe has a very thin wall and when the pressure exerted thereon byring 31 is heavy.

The apparatus of Fig. 5 closely resembles that of Fig. 4. The majordifferences are that the annular groove 4| in coupling '42 has an innerwall 43 near its bottom which is substantially cy lindrical; the flaredend 44 of pipe 48 has a cylindrical lip 45 to seat on surface 43; andthe seal ring 46 is a. little larger in inside diameter than the outsidediameter of pipe 48, so that normallythere is no engagement of thethicker end of ring 46 with the outer surface of the pipe.

groove 8 will strongly resist any tendency of the pipe end to deformunder to by ring I4.

In Fig. 3 member 28 corresponds generally to member 5 of Fig. 1 but .hasan annular thread carrying flange 2| and a retaining ring 22 havingthreaded engagement in flange 2|. The pipe 23 has a thickened end.24 anda conical surface pressure applied there- 25inclined at an angle ofapproximately de-.

grees to the center line of pipe 23 and with the base of that surfacebeing nearer to the end of the pipe. The seal ring 26 has an outersurface 21 to engage the opposed cylindrical surface 28 t in member 28,abuts at its thick end against threaded ring 22 and has a conicalsurface 29 extending from its thin end toward the thick end at an angleof approximately 44 degrees to the center line of pipe 23.

The sealing action of the apparatus of Fig. 3 is of the apparatus ofFigs. 1 and b I In Fig. 4 the pipe 39 has a flared end 3| whose outersurface 32 is conical and is inclined at an angle of about 20 degrees tothe longitudinal 1 center line of the pipe, with the base of-the conicalsurface being nearer to the open end of the pipe and whose inner surfacerests on the inner inclined surface 33 of coupling 34. That coupling hasan annular, flange portion 35 threaded interiorly to engage with anexteriorly threaded retaining ring 36 which abuts against the thick endof seal ring 31.

The latter ring has an outer substantially cylindrical surface. 38 andan inner conical surface 39 whose base is located near the inclinationis ap- I8 degrees to the longitudinal center in the assembled positionshown in this figure The seal ring 46, when pressure is exerted thereonby the retaining ring, makes substantially line contacts on its outerand inner surfaces with the coupling 42 and the conical surface of theflared portion 44 of Pipe 48, and these lines of contact are located insubstantially the same plane transverse to the longitudinal center lineof the pipe.

In Fig. 6 the end of pipe 58 is flanged, as at 5|, and is provided withan annular recess 52 having a substantially cylindrical inner sidesurface '53. The flange 5| is provided with threaded openings to receivestuds 54 carrying nuts'55. The end of pipe 56 has a lip 51 to entergroove 52 and a, substantially cylindrical surface to engage withsurface 53. The outer surface 58 of lip 51 is substantially conical andis inclined at an angle of approximately 45 degrees to the longitudinalcenter line of pipe 56, and when the lip is this conical surface isopposed to a substantially cylindrical surface 59 of flange 5|, and,together therewith, partly defines an annular stantially triangular incross-section.

Retainer ring 60 has a plurality of openings thru which studs 54 passand is provided with a seal flange 6| which is generally triangular incross-section and which may extend into the annular triangular spacebetween surfaces 58 and space sub- '59. The surface 62 of flange 6|opposed to surface 58 and pipe 56 is conical, is inclined at an angle ofabout 44 degrees to the longitudinal center line of pipe 56, the basesof conical surfaces 58 and 62 being disposed in substantially the sameplane transverse to the longitudinal center line of the pipe 58. 1

When the nuts 55 are turned on studs 54 to urge ring 68 toward flange5|,. the conical surfaces 58 and 62 make a substantially'line contactand a similar contact is made between the outer surface of seal flange6| andthe inner surface 59. of flange 5|, thereby forming line contactsin substantially the same transverse plane whichefl'ectively seal thejoint between pipes 56 and 56-against escapeof fluid under pressurebetween their ends. It will be understood that, as has been mentioned inconnection with previously described figures, the wall thickness of';-.pipes 08 and It may be other than the thick- 1 the sealing forcesare applied.

In Fig. 'I the pipe has a flared end portion- 80 and a substantiallycylindrical lip 81. The out- 'er surface 08 of the flared portion 88 isconical, is inclined at an angle of about 45 degrees to the longitudinalcenter line of the pipetand its base is near the lip portion 81. Thecoupling 88 has a flange l0 threaded to receive studs II which carrynuts I2. The coupling is provided with an annular groove I8 to receivethe lip 61 and part of the flared portion 88 of pipe 85. The innersurface ll of this groove 18 is inclined to engage the inner surface offlared portion 88 of'pipe 85.

The retaining and sealing ring 18 is quite like ring ll of Fig. 1 and 00of Fig.5. It has a sealing flange with an outer surface 11 to engagesurface 18 of groove 18 in coupling 68 and an inner conical surface l9which is inclined at an angle of approximately 44 degrees to thelongitudinal center line of pipe 85. when the ring is urged into groove18 the flange I0, near its thin end, makes substantially line contactswith surfaces I8 and 68 and thereby effectively seals against escape offluid under pressure thru groove I8.

It will be noted that outer surface 11 of flange I0 is slightly conicaland that the flange I0 may formed on either side of the ring.with theopposed surfaces of flange 81 and flared portion st of pipe 80. whenring 88 is turned to urge ring 80 into groove 84 substantially linecontacts are made between the outer and inner surfaces of ring 80 withthe opposed surfaces 8I and 88 and the joint is effectively sealedagainst escape of fluid under pressure between the pipe ends. As hasjust been described in connection with the apparatus of Fig. 7, pressureexerted by ring 88 on seal ring 80 may deform flange 81 substantiallyalong line E. The righthand sides of the threads on flange 81 aredisposed substantially at right angles to the direction of movement ofthe flange when it is deflected about line E. By reason of thisarrangement of threads sealing forces tending to deform flange 81 resultin increased sealing effect between ring 80 and flange 81 and pipe 80;and the same result occurs when forces are applied to the pipes tendingto sepa v rate them axially from one another.

In Fig. 9 pipe I00 has a flared end IOI having a conical outer surfaceI02 and a lip portion I8 having substantially cylindrical outer andinner surfaces I 08 and I05. The coupling I08 has an axially extendinggroove with cylindrical side walls to receive the lip portion I08 and tosupport it internally by engaging with surface I04 of the latter.Conical surface I02 of pipe I00 is be deformed radially inward to asmall extent before the surface I8 of groove 18 will engage surface 11of flange 10 for the full overlapping axial lengths of those surfaces.When nuts I2 urge ring II toward flange 10 force is exerted in thedirection of arrow A, and force is exerted on the flange as indicated byarrowB. Since the groove 18 is fairly deep, the tendency of these forcesis to bend or deform the flange substantial- 1y on line C withcoincident movement of flange I0 along the line generally indicated byarrow D. Any tendency of flange I0 to bend along line C and move in thedirection of arrow D, will result in greater pressure being exerted bythe flange I0 on flange I0 of ring 15, and by the latter flange. onconical surface 68 of flared portion 88 of pipe 05. Thus, as the sealingproducing force exerted on ring 18 increases beyond the amount necessaryto cause deflection of flange 10, the sealing action increases.Furthermore, this sealing action also increases when forces are appliedto pipes 88 and 88 in a direction tending to separate them axially fromone another.

In Fig. 8 the pipe 80 has a flared portion 8I and a lip portion 82. Theouter surface 88 of flared portion 8I is conical, is inclined at anangle of about 45 degrees to the longitudinal center line of, pipe 80and its base is near the lip portion 82. The lip portion 82 and part ofthe flared portion M of pipe 80 extend into an annular groove 84 in pipe85, part 88 of the inner surface of this groove bearing against theinner surface of the flared portion 8| of tube 80. Pipe 80 has anexteriorly threaded flange portion 81 v to receive an interiorlythreaded ring 88 which has an inwardly projecting flange 88 to abutagainst the thick end of seal ring 80 which projects into the annularspace between surface 8| of groove 88 and conical surface 88 of flaredportion 8| of pipe 80. The outer and inner surfaces 82 and 88 of ring 80are conical, their bases'being near the thin end of the ring and theinclination of these surfaces being such that annular *angular spaces ofapproximately one degree were inclined at an angle of about 45 degreesto the longitudinal axis of the pipe while surface III is inclined at 43degrees. Coupling I08 carries a plurality of studs I0'I similar to thoseshown in Figures 1 and 6 and a retaining ring I08 is mounted on thosestuds for movement toward the coupling I08 by actuation of nuts I08 onstuds I01.

I} sealing ring H0 is positioned between the conical surface I02 of pipeI00 and the opposed cylindrical surface of coupling I06. The innersurface III of ring H0 is conical and inclined at an angle of about twodegrees to the surface I02, the bases of conical surfaces I02 and IIIbeing engageable on a circumferentially continuous line near the thinedge of ring III. Between the sealing ring H0 and retaining ring I08 twodeformable packing rings II2 are disposed.

When the pipe and coupling are assembled as shown in this figure andretaining ring I08 is pressed against the adjacent packing II2 the twopackings II2 are pressed together and against the adjacent end of thesealing ring IIO with the result that conical surface III, engages theconical surface I02 and is deflected outwardly of coupling I08, Theresult of this action is the establishment of two substantially linecontacts between the outer and inner surfaces of ring H0 near its thinedge with the coupling and with the pipe. Pressure applied by ring I08to packings I I2 deforms them radially outwardly and inwardly intosealing contact with the outer surface of pipe H0 and the opposedcylindrical surface of coupling I00. In other words, pressure appliedaxially by ring I08 is transmitted through the packings and against thering H0 and the same force acts to deform the fluid like packings II2radially against the pipe and coupling.

In Fig. 10 pipe I has an end portion I8I which isflared outwardly andhas inner and outer curved surfaces I82 and I88 which are substantia-llyconical. Coupling I84 has an inner surface I85v which is substantiallycylindrical and projects into the space between surfaces I85 and I 36.

7 Coupling I34 is provided with studs I31 and a retaining ring I38thereon, both quite like the studs and rings in Fig. 9. Sealing ring I39has a substantially cylindrical outer surface and a curved butsubstantially conical inner surface I40. The radius of curvature ofsurface I40 is slightly greater than that of surface I33 so that anangular space of approximately 1 or 2 degrees exists between ring I39and portion- I3l of the pipe when the two are in assembled positionunder light pressure. Packing I is disposed between the retaining ringI38 and sealing ring I39 and resembles in material and operation thepackings II2 and'I26 of Fig. 9.

When ring I38 exerts pressure on packing Ill sealing ring I39 is pressedinto contact near its thin edge with surface I33 of pipe I30 and is alsodeflected outwardly into contact with surface I35 of coupling I34. Thesetwo contacts are circumferentially continuous, substantially linecontacts and are located approximately in a plane extending transverselyof the longitudinal center line of pipe I30.

It will be understood that the flange portion I6 of ring I4 of Figs. 1and 2 need not be cut away to receive ring I8 but that on the contraryring I4 of those figures may be substantially like ring I5 of Fig. 7.correspondingly it will be understood that ringbll of Fig. 6 or ring ofFig. 7

may be cut away and provided with a ring of different material as isillustrated by ring II! in Figs. 1 and 2. Indeed the sealing rings ofFigs. 3, 4, 5, 8 and 9 may similarly be provided with harder metalportions. stood that retainer rings of the screw threaded type may besubstituted for those of the stud carried type and vice versa and thatretainer rings of forms other than those here illustrated may also beused when desired.

It will also be understood that the angularity of the conical surfacesin each of the foregoing embodiments of the invention may vary withinwide limits. In Fig. 4 the angularity of surface 32 is 18 degrees whilein-Fig. 1 the angularity of surface II is 4.4 degrees. The range ofangularities should not be less than approximately 15 degrees or greaterthan approximately 75 degrees except under special conditionsandangularities between degrees and 60 degrees are preferred for mostconditions and applications.

Having thus described several embodiments of the present invention sothat those skilled in the art may be able to understand and practice thepresent invention,-I state that what I desire to secure by Lettersclaimed. What is claimed is:

A fluid seal comprising a bodyhaving an Patent is defined in what is Hopening and 'a rigid projection having a substantially cylindricalsurface surrounding said open ing, a member aligned with said openingand having an outer conical surface disposed within said cylindricalsurface, an annular, wedge-shaped, sealing ring having an inner surfaceinclined at an angle of approximately 2 to said conical surface, saidring making circumferential fluid seal- 1 ing contact near itsthinnerend in substantially the same transverse plane with said cylindrical 1andconical surfaces, the contact of said ring with the said conicalsurface being substantially only a line'contact when fluid pressure inthe body is low and increasing in width as fluid pressure in I the bodyincreases, and means secured to the body for maintaining said ring insaid sealing contact vwith said member and body.

Also it will be under- 2. A fluid seal comprising a. body having anopening, an annular abutment surface surrounding said opening, and arigid projection having a 3 cylindrical surface surrounding saidabutment 5. surface, a pipe aligned with said opening, having an innersurface supported on said abutment surface and having an outer conicalsurface disposed within said cylindrical surface, an annular wedgeashaped sealing ring having an inner surface in- 10 clined at an angle ofapproximately 2 to said conical surface, said ring makingcircumferential fluid sealing contact near its thinner end insubstantially the same transverse plane with said cylindrical andconical surfaces, the contact of 5 said ring with the said conicalsurface being sub-.

stantially omy a line contact when fluid pressure I in the pipe is lowand increasing in width as fluid pressure in the pipe increases, andmeans secured \to the body for maintaining said ring in said 'seala 2oing contact with said pipe and body.

3. A fluid seal comprising a body having an opening, a conical abutmentsurface surrounding said opening, and a rigid projection having acylindrical surface surrounding said abutment sur- 5 face, a pipealigned with said opening having an inner conical surface makingcircumferential.

sealing contact with said abutment surface, and having an outer conicalsurface disposed 'within said cylindrical surface, an annular, wedge:

shaped, sealing ring having an inner surface inclined at an angle ofapproximately 2 to said outer conical surface, said ring makingcircumferential, fluid sealing contact near its thinner end insubstantially the same transverse plane I with said cylindrical andconical surfaces, the contact of said ring with the said conical surface:being substantially only a line contact when fluid pressure in the pipeisjlow and increasing in width as fluid pressure in the pipe increases,and means 40 secured to the body for maintaining said ring in saidsealing contact with said pipe and body.

4. A fluid seal comprising a, body having an opening and a rigidprojection having a substantially cylindrical surface surrounding saidopening an outer conical surface disposedwithin said cylindricalsurface, an annular, wedge-shaped, sealing ring having an inner surfaceinclined at an angle of approximately2 to said conical surface, saidring making circumferential fluid sealing contact near its thinner endin substantially the same transverse plane with said cylindrical andconical surfaces, the contact of said ring with the said conical surfacebeing substantially only a body increases, deformable packing betweensaid cylindrical and conical surfaces at the thicker end of said ring,and means secured to the body for ring in the recess about said member,said ring having an outer surface making an outer, circuming, a memberaligned with said opening and hav-' line contact when fluid pressure inthe body is low I and increasing in width as fluid pressure in thepressing said packing against said ring and de-- said sealing contactwith 5. A fluid-seal comprising a unitary body havposed to saidcylindrical surface, said body and g I ferential sealing contact withsaid cylindrical surface and having a conical inner surface.in-'-REFERENCES CITED clined at a small angle to the outer conical surface ofsaid member and making an inner, cir-- The following references are 0!record in the cumferentlal, fluid sealing contact near its thinme Ofthis P nt: ner end with said outer conical surface; said in- 5 UNITEDSTATES PATENTS ner contact being substantially only a line contact whenfluid pressure in the body is low and Number Name Date increasing inwidth as the fluid pressure 111- 1390325 I schnaier 1931 creases, andmeans connected to the body 'for 2,112,239 Guamaschem 29, 1933maintaining the ring in said sealing contact with 10 2,247,031 NortonJ1me 1941 said member and said body. FOREIGN PATENTS ms C. HOBBS NumberCountry 525,241 Great Britain Aug. 23, 1940

